Data Merge - SvelteKit

Generate personalized designs from a single template by merging external data into CE.SDK templates using text variables and placeholder blocks.

Data Merge example showing personalized business card design

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Data merge generates multiple personalized designs from a single template by replacing variable content with external data. Use it for certificates, badges, team cards, or any design requiring consistent layout with varying content.

import type { EditorPlugin, EditorPluginContext } from '@cesdk/cesdk-js';
import packageJson from './package.json';

/**
 * CE.SDK Plugin: Data Merge Guide
 *
 * Demonstrates merging external data into templates:
 * - Setting text variables with engine.variable.setString()
 * - Finding variables with engine.variable.findAll()
 * - Finding blocks by name with engine.block.findByName()
 * - Updating image content in placeholder blocks
 * - Exporting personalized designs
 */
class Example implements EditorPlugin {
  name = packageJson.name;

  version = packageJson.version;

  async initialize({ cesdk }: EditorPluginContext): Promise<void> {
    if (!cesdk) {
      throw new Error('CE.SDK instance is required for this plugin');
    }

    // Initialize CE.SDK with Design mode and load asset sources
    await cesdk.addDefaultAssetSources();
    await cesdk.addDemoAssetSources({
      sceneMode: 'Design',
      withUploadAssetSources: true
    });
    await cesdk.createDesignScene();

    const engine = cesdk.engine;
    const page = engine.block.findByType('page')[0];

    // Set page dimensions for a business card layout
    engine.block.setWidth(page, 800);
    engine.block.setHeight(page, 400);

    // Sample data to merge into the template
    const sampleData = {
      name: 'Alex Smith',
      title: 'Creative Developer',
      email: 'alex.smith@example.com',
      photoUrl: 'https://img.ly/static/ubq_samples/sample_1.jpg'
    };

    // Create a profile photo block with a semantic name
    const photoBlock = engine.block.create('graphic');
    engine.block.setShape(photoBlock, engine.block.createShape('rect'));
    const photoFill = engine.block.createFill('image');
    engine.block.setString(
      photoFill,
      'fill/image/imageFileURI',
      sampleData.photoUrl
    );
    engine.block.setFill(photoBlock, photoFill);
    engine.block.setWidth(photoBlock, 150);
    engine.block.setHeight(photoBlock, 150);
    engine.block.setPositionX(photoBlock, 50);
    engine.block.setPositionY(photoBlock, 125);
    engine.block.setName(photoBlock, 'profile-photo');
    engine.block.appendChild(page, photoBlock);

    // Create a text block with variable placeholders
    const textBlock = engine.block.create('text');
    const textContent = `{{name}}
{{title}}
{{email}}`;
    engine.block.replaceText(textBlock, textContent);
    engine.block.setWidthMode(textBlock, 'Auto');
    engine.block.setHeightMode(textBlock, 'Auto');
    engine.block.setFloat(textBlock, 'text/fontSize', 32);
    engine.block.setPositionX(textBlock, 230);
    engine.block.setPositionY(textBlock, 140);
    engine.block.appendChild(page, textBlock);

    // Set the variable values from data
    engine.variable.setString('name', sampleData.name);
    engine.variable.setString('title', sampleData.title);
    engine.variable.setString('email', sampleData.email);

    // Discover all variables in the scene
    const variables = engine.variable.findAll();
    console.log('Variables in scene:', variables);

    // Check if the text block references any variables
    const hasVariables = engine.block.referencesAnyVariables(textBlock);
    console.log('Text block has variables:', hasVariables);

    // Find blocks by their semantic name
    const [foundPhotoBlock] = engine.block.findByName('profile-photo');
    if (foundPhotoBlock) {
      console.log('Found profile-photo block:', foundPhotoBlock);

      // Update the image content
      const fill = engine.block.getFill(foundPhotoBlock);
      engine.block.setString(
        fill,
        'fill/image/imageFileURI',
        'https://img.ly/static/ubq_samples/sample_2.jpg'
      );
    }

    // Export the personalized design
    const blob = await engine.block.export(page, { mimeType: 'image/png' });
    console.log('Exported PNG blob:', blob.size, 'bytes');

    // Create a download link for the exported image
    const url = URL.createObjectURL(blob);
    console.log('Download URL created:', url);

    // Select the text block to show the variable values
    engine.block.select(textBlock);

    console.log(
      'Data merge guide initialized. Try changing variable values in the console.'
    );
  }
}

export default Example;

This guide covers how to prepare templates with variables, set values from data, and export personalized designs.

Initialize the Editor#

We start by initializing CE.SDK with a Design scene and setting up the page dimensions for our template.

// Initialize CE.SDK with Design mode and load asset sources
await cesdk.addDefaultAssetSources();
await cesdk.addDemoAssetSources({
  sceneMode: 'Design',
  withUploadAssetSources: true
});
await cesdk.createDesignScene();

const engine = cesdk.engine;
const page = engine.block.findByType('page')[0];

// Set page dimensions for a business card layout
engine.block.setWidth(page, 800);
engine.block.setHeight(page, 400);

Prepare Sample Data#

In a real application, data comes from a CSV file, database, or API. Here we define a sample record with the fields we want to merge into the template.

// Sample data to merge into the template
const sampleData = {
  name: 'Alex Smith',
  title: 'Creative Developer',
  email: 'alex.smith@example.com',
  photoUrl: 'https://img.ly/static/ubq_samples/sample_1.jpg'
};

Each data record contains field names that map to template variables and placeholder blocks.

Create Template Layout#

We build the template by creating blocks and assigning semantic names. The profile photo block uses setName() so we can find and update it later.

// Create a profile photo block with a semantic name
const photoBlock = engine.block.create('graphic');
engine.block.setShape(photoBlock, engine.block.createShape('rect'));
const photoFill = engine.block.createFill('image');
engine.block.setString(
  photoFill,
  'fill/image/imageFileURI',
  sampleData.photoUrl
);
engine.block.setFill(photoBlock, photoFill);
engine.block.setWidth(photoBlock, 150);
engine.block.setHeight(photoBlock, 150);
engine.block.setPositionX(photoBlock, 50);
engine.block.setPositionY(photoBlock, 125);
engine.block.setName(photoBlock, 'profile-photo');
engine.block.appendChild(page, photoBlock);

Using semantic names like profile-photo makes it easy to locate and modify blocks when processing different data records.

Add Text with Variables#

Text variables use double curly brace syntax: {{variableName}}. We create a text block with variable placeholders for name, title, and email.

    // Create a text block with variable placeholders
    const textBlock = engine.block.create('text');
    const textContent = `{{name}}
{{title}}
{{email}}`;
    engine.block.replaceText(textBlock, textContent);
    engine.block.setWidthMode(textBlock, 'Auto');
    engine.block.setHeightMode(textBlock, 'Auto');
    engine.block.setFloat(textBlock, 'text/fontSize', 32);
    engine.block.setPositionX(textBlock, 230);
    engine.block.setPositionY(textBlock, 140);
    engine.block.appendChild(page, textBlock);

Variables in text blocks automatically display their values when set through the Variable API.

Set Variable Values#

We use engine.variable.setString() to define the value for each variable. When a variable is set, all text blocks referencing that variable update automatically.

// Set the variable values from data
engine.variable.setString('name', sampleData.name);
engine.variable.setString('title', sampleData.title);
engine.variable.setString('email', sampleData.email);

Variable values persist throughout the engine session. Setting a variable to a new value updates all references immediately.

Discover Variables#

Use engine.variable.findAll() to discover which variables exist in the scene. Use engine.block.referencesAnyVariables() to check if a specific block contains variable references.

// Discover all variables in the scene
const variables = engine.variable.findAll();
console.log('Variables in scene:', variables);

// Check if the text block references any variables
const hasVariables = engine.block.referencesAnyVariables(textBlock);
console.log('Text block has variables:', hasVariables);

This is useful when loading existing templates to determine which data fields are required.

Find and Update Placeholder Blocks#

Use engine.block.findByName() to locate blocks by their semantic name. Once found, you can update properties like image content by modifying the fill URI.

// Find blocks by their semantic name
const [foundPhotoBlock] = engine.block.findByName('profile-photo');
if (foundPhotoBlock) {
  console.log('Found profile-photo block:', foundPhotoBlock);

  // Update the image content
  const fill = engine.block.getFill(foundPhotoBlock);
  engine.block.setString(
    fill,
    'fill/image/imageFileURI',
    'https://img.ly/static/ubq_samples/sample_2.jpg'
  );
}

This pattern works well for updating profile photos, logos, or other image placeholders in templates.

Export the Design#

After merging data into the template, export the personalized design using engine.block.export().

// Export the personalized design
const blob = await engine.block.export(page, { mimeType: 'image/png' });
console.log('Exported PNG blob:', blob.size, 'bytes');

// Create a download link for the exported image
const url = URL.createObjectURL(blob);
console.log('Download URL created:', url);

You can export to PNG, JPEG, WebP, or PDF formats. For batch processing, collect blobs in an array or write directly to a file system.

Troubleshooting#

Variables Not Rendering#

If variable placeholders show instead of values:

Verify the variable name matches exactly (case-sensitive)
Use engine.variable.findAll() to check which variables are defined
Ensure engine.variable.setString() was called before rendering

Block Not Found#

If findByName() returns an empty array:

Check the block name was set with engine.block.setName()
Verify the name string matches exactly (case-sensitive)
Ensure the block exists in the current scene

Image Not Updating#

If placeholder images don’t update:

Get the fill block first with engine.block.getFill()
Use the correct property path: fill/image/imageFileURI
Verify the image URL is accessible and valid

API Reference#

Method	Description
`engine.variable.setString(name, value)`	Set a text variable’s value
`engine.variable.getString(name)`	Get a text variable’s value
`engine.variable.findAll()`	List all variable names in the scene
`engine.variable.remove(name)`	Remove a variable
`engine.block.findByName(name)`	Find blocks by their semantic name
`engine.block.setName(block, name)`	Set a block’s semantic name
`engine.block.replaceText(block, text)`	Replace text content in a text block
`engine.block.referencesAnyVariables(block)`	Check if block contains variable references
`engine.block.getFill(block)`	Get the fill block of a design block
`engine.block.setString(block, property, value)`	Set a string property value
`engine.block.export(block, options)`	Export a block to an image format